parseInt(); 转换成整数
var a="13.9";
var b=parseInt(a);
console.log(b); 13
console.log(typeof b) number
console.log(isNaN (b)); false
var a=13.9;
var b=parseInt(a);
console.log(b); 13
console.log(typeof b); number
console.log(isNaN (b)) false
parseInt可以使字符串转换为数字也可以使小数点变为整数
parseFloat(); 转换成小数
var a="1.01";
var b=parseFloat(a);
console.log(b); 1.01
console.log(typeof b); number
console.log(isNaN (b)); false
var a=5;
var b=parseFloat(a);
console.log(b); 5
console.log(typeof b); number 带不带双引号都是number
console.log(isNaN (b)); false
var a=.5;
var b=parseFloat(a);
console.log(b); 0.5
console.log(typeof b) number
console.log(isNaN (b)); false
Number(); 转换成number类型
var a="5";
var b=Number(a);
console.log(b); 5
console.log(typeof b); number
console.log(isNaN (b)); false
toString(); 转换成字符串
var a=ture;
var b=a.toString();
console.log(b); ture
console.log(typeof b) string
var a=12;
var b=a.toString();
console.log(b); 12
console.log(typeof b); string
console.log(isNaN (b)); false
toFixed(); 按要求保留小数位数
var a=13.95685;
var b=a.toFixed(3); toFixed后输入你想保留的位数
console.log(b); 13.958
console.log(typeof b) string
